Method and apparatus for batching-out items such as poultry pieces

ABSTRACT

A batcher apparatus having a weighing station ( 4 ) for arriving items and a sorting-out station ( 6 ) with transfer mechanism for selectively transferring the weighed items to a plurality of receiver stations ( 18, 18′, 18″ ). According to the invention two or more receiver stations may be used as substations ( 18′, 18″ ) being allocated items weightwise belonging to the same batch ( 26 ), whereby it is possible to allocate to each batch item, which are selected not only based on their weight, but additionally based on other criteria such as type of item in connection with co-batching of different types of poultry parts to be batched separately in subbatches which are then merged into the full batch. Also, items may be allocated to one substation or another in order to thereafter be acted upon in a specific manner, e.g. for some items to be turned or marked.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method and an apparatus for thebatching out of items with non-uniform weights, in particular foodstuffitems. The invention is closely linked with the so-called gradertechnique, involving the use of a portioning-out apparatus havingconveyor means for moving a flow of items through a dynamic weighingstation and thereafter along a sorting-Out path, along which there isarranged a row of receiver stations with associated diverter meanswhich, controlled from a control unit connected with the weighingstation, can be actuated in a selective manner in order to divert theindividual items into respective receiver stations for building uptherein batches of items amounting to at least a predetermined totalminimum weight or target weight, within given limits.

2. Description of Related Art

The prior art, e.g. as disclosed in GB 2 116 732 and WO 96/08322,provides for the repeated building up of one full batch in each of thereceiver stations, but in particular in WO 96/08322, it is indicatedthat it is perfectly possible to operate with different target weightsin or for different receiver stations, hereinafter also referred to as“bins.” Such a differentiation is useful for different purposes, asdiscussed in more detail below, but already at this place, it should beemphasized that a major aspect of the present invention is the use of atleast some. of the receiver stations as substations for receivingselected items to be merged into one full batch with a predeterminedtarget weight, and thus, holding items received from more than onereceiver station.

This will introduce a possibility of co-batching items selected on thebasis of criteria other than or in addition to the weight criterion,whether referring to characteristics of she incoming items, e.g. coloror “type”, or to acts to be performed on the items upon their deliveryto one or another substation, respectively, e.g. in being selectivelyprovided with a color marking or being orientationally reversed orotherwise treated or handled in or at the outlet side of the respectivereceiver substations, before the collection of the items in the “finalbatch.”

A highly relevant example of the use of the invention pertains to theindustrial handling and packaging of the cut pieces of parted poultry,with specific reference to the huge chicken industry. In thatconnection, by way of example, it is a widespread practice to produceso-called “catering packages,” each holding four isolated groups ofpredetermined numbers of breast pieces, thigh pieces, leg pieces andwings, respectively, said groups having part-weights such that when theyare brought together they will amount to a predetermined total weight. Atypical example will be to produce packages (boxes),.each with four bagscontaining 24 pieces, i.e., with a total content of 96 pieces with atotal weight of 34 lbs. for the pieces from the lower weight class and38 lbs. for those from the higher weight class. A suitable part-weightis determined for each of the four bags, thus, for example, for the“light” pieces

12.7 lb breast

10.2 lb thigh

6.2 lb wings

4.9 lb lower leg (“drumstick”)

in all

34.0 lb for 96 pieces.

In order to maintain these part-weights in a reasonably reliable manner,in practice it will be unavoidable that some overweight will beinvolved, and when these overweights are summed up in the composition ofthe four bags, the result can be a quite considerable overweight(“give-away”) of each of the total packages. To these costs must beadded those of additional labor that may be needed with larger highcapacity packing lines.

Using the grader technique for the production of the individual “bags”will greatly facilitate the building up of the required subgroupstherein, even with a minimized overweight thereof, yet still with someoverweight and still with operators having to merge the different bagsinto final packages.

SUMMARY

According to the present invention, however, it will no longer beimportant to use the criterion that each of the four “bags” mustabsolutely appear with an independent minimum weight. With themanually-controlled portioning-out, the criterion has actualsignificance in that, for the operators, it will be almost hopeless workboth to control a more-or-less correct bag filling and to carry out a“bag grouping” for fixed weight on the basis of bags whose weight canlie both slightly above and slightly below the specified “categoryweight,” but with the use of a suitable grader control this will not beany problem, in principle even completely without manual assistance. Thesystem can be programmed in such a way that in groups of four differentreceiver bins, the respective item portions are built up for the fillingof “bags” with more-or-less the desired own weight, but with the maincondition that the weight of the four bag portions together shall bedown as closely as possible to the prescribed total weight of the sum ofthe bags.

In practice, this will mean a drastic change with respect to theoverweight occurring in the total portions (“the boxes”), in that thiswill regularly be able to be reduced to a previously unobtainableminimum, while at the same time the operating work can be limited to anabsolute minimum. The available chicken pieces can be utilized withincreased efficiency without any noticeable inconvenience for theassociated customers. For these it will be quite without significancewhether a bag with, e.g., 24 leg pieces weighs slightly less thanexpected, if this is compensated for by corresponding overweightoccurring in some of the other bags. In such cases therefore, thecustomer is supplied with a fully useable and acceptable quantity.

Moreover, with the invention the work at the producers can be achievedwith a minimum of waste in the form of items or “bags” which are notsuitable for batching together with other items or bags for thebuilding-up of portions with reasonable relevant weight, and such aminimization, which does not concern the customers, will obviously alsobe of the greatest interest to the producer.

In order to achieve the desired result, the grader equipment must bekept informed concerning the kind of items successively supplied, i.e.,if the variance in the weight of said items is not sufficient in itselfto clearly identify the item types. If, for example, a leg piece from aheavy chicken weighs wore than a breast piece from a lighter chicken,the control equipment will not be able to clearly identify the itemtype, and consequently it may not have the possibility of being able toplace the item together with an item of the same kind. This problem canpossibly be overcome by using visual scanning equipment which canidentify the kind of successively arriving item, or by the equipmentfeeding the item being supervised by an operator who provides thecontrol equipment with a type-identifying code.

It is also possible to arrange the equipment which feeds the item to thegrader in such an operator-controlled way that the item per definitionwill be introduced in a predetermined type sequence, whereby the controlequipment will automatically be informed concerning the kind of itemsuccessively being supplied.

A further and highly realistic possibility is for the item to be fedalong separate tracks, from which the item are automatically transferredto the weighing line with associated automatic transfer ofidentification signals to the control computer. Moreover, there is thepossibility of being able to use two parallel weighing lines to whichtwo types of item are fed selectively, namely respective pairs of itemtypes, which in general have such great mutual weight difference thateach of the two weighing lines can themselves identify the item types.The items can, e.g., hereby be supplied in a coherent, irregular flow toa separating station where two operators transfer the respective itemtypes to each their weighing line, and ensure that the items are placedon these with sufficient space between them so that they can beidentified at the subsequent weighing.

On the level of principle, it will be possible to carry out thedisclosed method with the use of an ordinary grader, the control unit ofwhich is programmed so as to execute batching of the relevant numbers ofitems of different types up to a predetermined total target weight, andso as to thereby allocate the items of the different types to respectivedifferent receiver stations. Thus, the grader will make use of arelevant number of its ordinary receiver bins for the forming of onebatch, the item sub groups or “bags” being manually or automaticallyunloaded from the bins and brought together into one “box”.

For a grader according to the invention, however at least when the armis dedicated to operate exclusively with the relevant “multi productbatching”, it is preferred for the sake of simplicity to arrange for therelevant “sub bins” to be physically grouped close to each other and tobe in operative connection with outlet guide means leading to a cautionbatch collector station. The latter may be a container, a platform at abelt, from which, the received bags can be transferred to a relevant“box”, or the collector station may be the box itself, then the operatortakes care to place in each collector wits a box ready for directreception of a following batch. The bins or “receiver substations” areused for the bagging of the items, and the said outlet guide means maythen be constituted by a fixed chute installation leading the bags to aspecific collector site for each group of interrelated bins.

The invention is relevant whenever there is a reason to distinguishbetween items which, weightwise, can be accepted as belonging to onearid the earn batch, whatever the criterion of such distinguishing maybe. Specific “types” of items as discussed above will not be limited todifferent body parts of poultry, but may as well refer to a selectione.g. of three red apples in batches of ten red and green apples or sevenlarge slices of smoked salmon in batches of twenty larger and smallerslices. Also, if whole fishes are supplied with non-uniform orientation,it may be desirable to effect a turning of some of them once it has beendecided to which batch they should be allocated in order to ensure thatin that particular batch the fishes will be deposited generally withopposite orientations in order to effectively fill up a fish box to areasonably horizontal level. It follows that whenever the fishes aresupplied with uniform orientation it may or will be required to effect aturning of some of them upon their being allocated to a specific batch,and in this respect it is very convenient if or when such a turning canbe effected methodically for all items delivered to one receiversubstation, while in a counterpart station the items are received andtransferred to the collector box without being turned.

As discussed in more detail in PCT/DK99/00235, these turnings can beestablished in several different manners, however widely based on theseparation principle of the present invention.

Also, in connection with almost all kinds of foodstuff pieces there maybe pieces which are of equal weights, but are otherwise different invarious respects, be it with respect to color, specific dimensions suchas length, structure or partial damaging, and for a given batch it maybe desirable to load a box with “regular” pieces at one end of the boxand “irregular” pieces at the other end of the same box. According tothe invention, this is easily achievable once the relevant character ofthe pieces has been detected, e.a., by means of a vision system, viz, insupplying the selected pieces selectively to two different receiverstations, from which they are conveyed to the respective opposed endareas of a collector box, preferably along a common chute element.

In the following the invention will be described in more detail withreference to the drawing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a grader according to the invention,

FIG. 2 is a top view of a conventional grader operating with a modifiedmode of function in accordance with the invention,

FIG. 3 is an end view of a conventional grader,

FIG. 4 is a top view of a grader according to the invention,

FIG. 5 is an end view of a grader according to the invention, and

FIG. 6 is a calculation diagram.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a grader installation seen from above, the main parts beinga product supply section 2, a weighing section 4, a sorting section 6and a delivery station 8.

The supply section 2 has a supply conveyor 10 on which items to bebatched are fed in an irregular flow in the form of a combination of twodifferent types of items, which have not been sorted in any waybeforehand. The weighing station 4 has a conveyor belt 12 and isconnected with a control unit 14. The sorting section 6 has a conveyorbelt 16 which passes along a row of receiver stations each representedby a receiver 18 in the form of a bin with or without a bottom and, asshown at the opposite side of the belt 16, respective diverting wings 20which, as shown at 20′, are controllable to be swung inwardly over thebelt 16 so as to effectively divert a selected item to a selectedreceiver bin 18, governed by the control unit 14, all this being a wellknown technique.

A novel feature, however, is that at a majority of the receiver stationsthere is arranged, underneath different pairs of receiver bins 18′, 18″,a common chute 22, optionally with a middle partition 24, leading to acommon receiver area 26, e.g., holding a packaging box 28 to be changedupon receipt of a full batch of items. The receiver bins 18′, 18″ mayeven be combined into one long bin 30, with or without the common chute28 thereof having a middle partition 24.

At the infeed end of the sorter belt 16, whether before, in or justafter the weighing station 4, there may be arranged sensor meansgenerally designated 32, e.g., vision equipment, for recognizing andevaluating any relevant character of the incoming items, be it color,type, length, width, structure, completeness or the like. The unit 32 isconnected to the control unit 14 such that the latter, in its allocationdecisions, can decide whether a given item of a relevant weight forinclusion in a given batch should be delivered to one or the other oftwo “double bins” 18′ or 18″ in order to be deposited at one or theother end or half of a receiver box 29 or, respectively, to one or theother end area of a “long receiver bin 30” with the same purpose.

In some instances, there will be no restriction with respect todepositing of items of different characters at one or the other end ofthe boxes 28, and in such cases, of course, there will be no need forthe partition 24 on the chute 22.

As mentioned, while a registered characteristic of a weightwise relevantitem may be decisive for its allocation to one or another subreceiverstation (18′ or 18″), another criterion for such a selection may bebased on requirements for special acts to be performed on specific itemsof generally the same character allocated to the same collector area 26.As an example, FIG. 1 shows that, at one end of a “double bin” 30, therecan be provided a marking unit 34 operable, for some reason, to spraymark all items selected to be delivered to that end of the long bin 30,while the items delivered at the opposite end of the long bin will notbe correspondingly marked. Other successive acts could be performed,such as a turning of non-symmetrical items in order to merge the itemsin substantially horizontal layers in the boxes 29. In such cases, ofcourse, there will be no need for any “character detector” 32.

FIG. 2 shows a grader apparatus having a supply section 2 with a supplyconveyor 10 on which frozen chicken pieces are fed in an irregular flowin the form of a combination of the four already mentioned types ofpieces, without these having being sorted in any way beforehand. Alongeach of the opposite side edges of this conveyor is a narrower conveyor36, 36′, and these conveyors run under respective cell-divided feederunits 38, 38′ in such a manner that the indicated operators at theopposing sides can grip the chicken pieces arriving on the centralconveyor for selective placing of these in associated, dedicated cellsmarked with the letters A, B, C and D.

The letters can, for example, refer to the following types of pieces:

A=wings

B=breast pieces

C=upper leg pieces

D=lower leg pieces (drumsticks)

It is hereby ensured that type-determined, mutually separated pieces aresupplied to the conveyors 36, 36′ and that these are in well-definedpositions on the conveyors. As will be seen, it has been found expedientthat each of two operators at the respective two sides shall concentrateonly on the selection of the two different types of pieces, such as A, Cand B, D respectively, but otherwise it will apply that a correspondingselection can be made by automatic means, e.g., by using visual scanningequipment. The object of the relevant selection and selective placing onthe conveyors 36, 36′ is to make it possible for the subsequent weighingand control unit 4 to keep track of the type of the passing itemsregardless of whether they overlap one another in weight.

The conveyors 36, 36′ deliver the items to the through-going conveyorsections 12, 12′ in the weighing station 4, in which the type and theweight of the individual, mutually separated items are registered in theassociated computer 14.

Thereafter, the weighing conveyors 12,12′ deliver the items to theconveyors 16,16′ which extend along the sorting section 6. Along this atthe opposite outer edges of the conveyors 16 and 16′, sweeper blades 20are arranged which can be swung in over the respective conveyors undercontrol from the weighing computer 14, 50 that each conveyed item, suchas shown at 20′, is able to be directed for selective delivery to eachof a number of stationary receiving bins 40 arranged in a central row inbetween the conveyors 16 and 16′, controlled by the weighing computer.It is thereby possible to sort out the fed pieces to the receiving bins40, each of which is dedicated to the receipt of pieces of identicaltype, designated A, B, C and D, respectively.

In FIG. 3, it is shown that sideways-sloping discharge chutes 42 canextend from the bottom of the receiving bins to respective bag holders44, so that each bin, after or during its reception of item up to acertain weight, can be emptied into a bag 46, which, standing on a tableplate 47, can be loosened from the bag holder by an operator and, afterbeing closed, can be pushed in on to a central conveyor 48, thedischarge end of which emerges at the delivery station 8. From here,the, bags can be removed for packing in boxes, which typicallyaccommodate four bags, i.e., one of each of the four types A, B, C andD, and each containing, e.g., 24 pieces of the respective products.These packages are called catering-packs, and efforts must be made atthe portioning-out to ensure that the each bag with 24 pieces achieves atarget weight which will give the required target weight of the fourbags, e.g., 34 or 38 lbs.

From the above it will be understood that arbitrary A, B, C and D bagscan be removed from the portioning-out line and conveyed together forpacking in the said portion boxes, and according to conventionalpractice, the operator shall thus merely ensure that a group of thesefour different bag types appear at each delivery, regardless of fromwhich receiving bin they originate.

In practice this means that, in order to avoid underweight, work must beeffected with a certain overweight tolerance on the individual weights,and the smaller this tolerance, the greater will, be the number ofindividual products which cannot be placed in any of those portionswhich are being batched, and these products must therefore be fed atover the ends of the conveyors 16 and 16′ in the delivery area forrecirculation. The effect of this can be an appreciable reduction in theworking capacity of the grader, and the supplier is therefore tempted toaccept a distinct overweight, which can result in a satisfactory andcostly fourfold overweight in the total packaging.

As will be seen from FIG. 2, a smaller number of receiving bins 40′ areprovided at the discharge end of the conveyors 16 and 16′, and these aremarked with all four letters A, B, C and D. This provides for thepossibility of being able to intercept items which are not able to beplaced in any of the bins 40, in that these item, i.e., all four types,can thus be collected in so-called ‘family’ packs or retail portions.The aim can thus be to collect portions up to a given total weight, herepossibly with a more generous tolerance for overweight.

With the invention, it is possible to make radical changes in theseconditions, so that the grader, with regard to the main task to becarried out, can work with high capacity when supplying total portionswith minimized overweight.

A first and very simple solution can be for an agreement to be enteredinto with the buyer, whereby the buyer accepts that in the totalpackages there can be a small percentage which are slightly underweightwithin a given limit. This could enable the general price for totalpackages to be lowered. The basis for this will be that the tolerancerequirements for the individual portion packages (the bags) will bereduced, and that a modest bag underweight can be tolerated. Because theunderweight can only be small, it will only arise in a small number ofpart-portions, and since in the complementary part-portions there canthus continue to arise a certain overweight, when the part-portions arebatched it will not be typical for these to comprise identicalunderweight portions, so that in by far the majority of cases one or twounderweight part-portions will be brought together with three or twooverweight portions, whereby there will generally arise a closeapproximation of the intended total weight.

Regardless of such agreement, an underweight total portion will occuronly extremely rarely, while the grader has had the advantage of beingable, to combine one or more underweight portions with one or moreoverweight portions, and herewith allowed fewer products to pass forrecirculation, i.e., has generally been able to work with increased,capacity and reduced total overweight.

A second and even better solution will be that the control unit, inaccordance with the same criteria, establishes an organized relationshipbetween every four or any other relevant number of adjacent receivingbins 40, in such a way that the batching of the product in these isdirected towards arriving at the predetermined full weight for the totalportion, with less importance directed to precise individual portionweights. The operator merely needs to know how the different receivingcontainers are related in groups. In this connection, it could behelpful for control lamps at the individual receiving stations not to belit simultaneously, e.g., at all four stations, until the total portionis ready to be delivered, regardless of whether one or more of the bins40 have already received the prescribed number of products and have beenready for emptying for some time.

A grader which is to work only in accordance with the invention will notneed to have lead-out blades 20 on both Sides of the bins 40 along thesection forward to the containers 40′, since these blades need only tobe provided opposite those bins with which they are required tocooperate.

FIG. 4 shows a grader installation with a sorting-out section which isespecially arranged to work in a more expedient manner in accordancewith the principle described above connection with the receiving bins 40in FIG. 2. Here, each of the bins 40 cf. FIG. 2 are divided in themiddle to form two individual bins 50, 50′ with lead-out blades 20 onboth sides of each set of bins, so that a complete bin set A-B-C-D, seenin the longitudinal direction of the grader, will take up only half thespace than is the case in FIG. 2. Each of the related double bins, i.e.,A, B and C, D, have a common discharge chute 52 to the same side (FIG.5), while the subsequent double pair of these containers have theirdischarge chutes 52 turned towards the opposite side, cf. FIG. 5. Foreach set of four individual containers, bag holders 44 will thus bedisposed only at the one side, while, the place on the support table 47,47′ for the bags 46 at the opposite side will be empty. Consequently,this free space can be used in an expedient manner for the accommodationof a box 54 which can be used by the operator for the collection ofthose bags which at the same side will appear with the next following orpreceding pair of double containers, after which the operator can pushthe filled box in on the discharge conveyor 48. Upon arrival at thedischarge area B, the boxes can. simply be transported further fordelivery as fully-finished package units.

Here, it will continue to be decisive to ensure via the control unitthat the product. build-up in each of the pairs of double containers 34(A, B, C, D) is controlled in such a way that the measured weightrelates predominantly to the whole of the product group A+B+C+D, ratherthan to the individual parts in these groups.

In FIG. 4 is shown a modified embodiment of the product supply station2. The parted pieces of poultry are fed in to run-through freezer 56,and from here they are conveyed to separation station 58 where twooperators 60, 60′ separate the items for the respective weighingconveyors 12 and 12′, and hereby ensure that the distance between theitems placed on these conveyors is such that it can be detected by theassociated weighing system 4 itself whether the passing items arerespectively A- or C-items or B- or D-items.

It is to be emphasized that the weighing function can be executed in anyweight determining manner, e.g., based on vision detection or onweighing means connected with an overhead structure for carrying theweighing station without the items being supported from beneath.

As suggested already in said WO 96/08322, the items should be suppliedin reasonable mixed formation in order to ensure a frequent occurrenceof each of the item types, and the grader may be programmed so as toeffect allocation of types to the different bins in different sequentialorders, one bin, for example, calling for A-B-C-D types, another forB-C-D-A types, and so forth, in order to ensure that at least most ofthe time there will be a need for each of the item types. This willapply especially to the already discussed consecutive building up ofrespective sub portion of items of different types, some sub portionswith some underweight allowed or preceded by other sub portions of someoverweight, this greatly facilitating the total batching work and thusincreasing the batching capacity and decreasing the giveaway.

The sequence pattern for the individual bins should not necessarily bepredetermined, insofar as the computer may well be programmed to makecoordinated decisions with respect to choice of “new type” for theindividual bins, specifically with the purpose of smoothing out thedemands for the different types so as to keep the general batchingcapacity high.

In practice, however, it is not a condition that the relevant subbatches should be built-up in a strictly consecutive manner, as thecontrolling computer can well handle a dual building up of all of thesub batches at the same time still aiming at a predetermined totaltarget weight of entire batch, but also, in combination, with respect tothe formation of the individual batches.

According to the present invention, it has been recognized that the sameprinciple is applicable in a simplified manner whenever the weightdistribution of or in the supplied flow of items can be anticipated,e.g., in connection with an intake of item supposed to be weightdistributed according to a “normal distribution” as expressed by aso-called Gauss-curve. Previously, viz, in the already mentioned GB 2116 32, it has been suggested to take advantage of such a know-edge inconnection with the batching of items of one single type, but it is now.realized that the same knowledge is perfectly usable in thebatching-together of item of different types, when the weightdistribution of these different types an be estimated beforehand,without relying on any specific histogrammatic recording or onsophisticated probability calculations. The main principle is that it ispossible, based to simple combinatory calculations, to merge item insuch a inner that during the building up of a batch the accumulatedtight will gradually approach a value, from which the batch in becompleted by one or more item of the average weight of the distribution,i.e. item most frequently occurring in the incoming flow of items,whereby the batches can be concluded in an expedient manner in order toensure a high batching capacity. Items clearly deviating from theaverage weight may be used at the beginning of each batching.

To illustrate this, in the present connection, FIG. 6 indicates acalculation model for the determination of “best choice” in allocatingitem to a selected bin when the same missing 4,3,2 and 1 item or item,respectively, in order build up therein a batch of 2×2 item of twodifferent types A and B. In connection with a natural weightdistribution the respective two types an ideal choice of the batchtarget weight, H, should be the double sum of the average weights of theitems of the respective types, or a well defined target range across oradjacent to this sum weight.

When a given bin is missing 1 item as represented by the line −1 in FIG.6, it will of course be either an A- or a B-item, as the partial batchwas put together so that just one item exhibiting the average weight ofthe relevant respective distribution (A or B). Such a weighed-in itemcan be quickly located and so allocated. When 2 items are missing, cf.line −2, these will be either 2 A-items, 2 B-items or 1 A- and 1 B-item,i.e., there wil be three options. The computer, knowing the availableand expected item types and weights according to the respective weightdistributions and also knowing the weights of the collected items in allof the bins missing two items, will then decide “best choice” for anynew item to be allocated to such a bin which, when thereafter missingone item in stage 1, will have the better likelihood of being built upto the target weight M. It will be understood that the required twoitems can be selected, each, within relatively broader weight ranges,insofar as they should only fulfill the condition that the sum of theirweights should build up the partial batch weight of the items in theselected bin to the point or narrow range, from which the batch can becompleted by one item from the average weight range of the items ofeither type A or type B.

When 3 items are missing (line −3), such items will be either one A-itemplus two B-items or one B-item plus two A-items, i.e., now with stillmore combination options that will satisfy the conditions for thebuilding up of the relevant partial batches to the stage where they missonly two items. Here again, the individual items can be selected from astill broader weight range of the respective item types, when only thesum of weight of the three items is sufficient to satisfy the conditionsof stage 2.

In step 4, which will be the first step of item selection for thebuilding up of a batch in any bin just requiring a first item, it willat least in principle be possible to select freely from the two types ofitems and from the entire range of the respective distributions,realizing the possibility of thereafter, in stage 3, further building upthe partial batch weight to satisfy the conditions of that stage.

It should be considered, however, that it will not always be possible toexploit all of the items of a given distribution, in particular, becausea selection of a first item from either end of the spread of thedistribution may make it practically impossible to thereafter arrive ata predetermined target weight. In such cases, it will be a preferredpossibility to sort out or neglect all of these extreme items, which arerelatively few in number and then accept that the effective weight rangeof the distribution is correspondingly restricted.

In FIG. 6, the course of sequence of the required calculations isillustrated in solid lines in two dimensions only, Linked with thehandling of but two different types of items, each exhibiting individualweight distributions. If items of three different types are involved,the same calculations can be extended to comprise even the presence of“C type item” in a third dimension as shown in dotted lines, and ifstill further types are added, it will thus be adequate to speak ofcalculations in a “multidimensional space”, as also proposed in WO96/08322 in connection with histogram based on probability calculations.

Some co-batching jobs may be connected with special conditions to beobserved. Thus, for the batching of different chicken parts in pairs, itmay be set as a condition or at least a preference that the parts in anypair should be of reasonable uniform weight, i.e., originating from thesame relatively narrow weight range, in order to look “natural.”Generally, the customers will not find it particularly remarkable if, ina packing with 2×4 chicken parts, the respective pairs of partsoriginate from chickens of pronounced different weight classes, whenonly the parts of the individual pairs are reasonably alike, and thegrader system, therefore, will still have good possibilities to mergeitems so as to form pairs or even larger numbers of items withsubstantially equal weights and yet arrive at batching results withacceptable tolerances out from a wide weight range of the respectivetypes of items.

In the foregoing, it has been assumed that the overall goal is to makeup batches holding a predetermined number of items amounting topredetermined target weights (weight ranges, weight distributions). Itis a still further aspect of the invention, however, that while it isstill desirable to work with one or more predetermined target weights,it will be practicable to renounce the requirement as to thepredetermined number of items in the batches. It has been found thatwith the aid of modern signal analysis equipment, whether operating inreal time or in high speed simulation mode, it will be possible for thebatching computer to recommend, generally or periodically, to build upall or some batches with another number of items in order to reach thetarget weight more economically (small give-away overweight, small rateof recycling of unplaceable items). Such a recommendation can beconveyed to a batching operator, who will then decide whether therecommendation should be followed, perhaps in view of other conditions,or the computer may be set to imply institute switches between differentnumbers of items in all or some of the batches whenever this is foundappropriate and permissible. In connection with co-batching of items ofdifferent types such shifts may be effected individually for each typeof items.

It will be appreciated that in connection with the invention it will bepossible to set up a long row of different batching conditions, relatingto

fixed or variable numbers of each or some of the respective types ofitems in each batch or in respective different batches;

fixed or variable target weight of each type of the respective items ineach batch, including fixed target weights for one or more types andvariable target weight for one or more other types;

different batching conditions for respective individual receivers orbins, including selection of different combinations of respective typesoff items;

fixed or variable batch weight with fixed or variable target weight ornumbers of respective types of items.

What is claimed is:
 1. A method of controlling operation of aweighing-out apparatus of the grader type having a weighing-in station,a sorting-out path, at least one row of receiver stations withassociated diverter means for enabling selective transfer of items tosaid receiver stations, a conveyor for moving articles serially throughsaid weighing-in station and along a sorting-out path, at least one rowof receiver stations arranged along said sorting-out path, a controlunit connected with the weighing-in station, comprising the steps of:serially conveying articles through said weighing-in station, weighingthe articles and conveying the articles weighed along said sorting-outpath, using said control unit to operate said diverter means in a mannereffecting an accumulative and weight determined build-up of desiredgroups of items in respective receiver stations, using at least two ofthe receiver stations as a single combined station, using the controlunit to allocate items to the each of the least two receiver stations ofthe combined station to define a final batch having an associated targetweight wherein allocation of an item to one of the at least two receiverstations of the combined station is controlled in order to compensatefor the weight of other of the at least two receiver stations in orderto provide a final batch weight within a predetermined tolerance; andmerging of items allocated to the at least two receiver stations of thecombined station.
 2. The method according to claim 1, wherein during theallocation of an item to one of the at least two receiver stations ofthe combined station an additional criteria related to the physicalcharacteristics of the item other than item weight is used along withitem weight to allocate the item to the receiver station of the combinedstation.
 3. The method according to claim 2, wherein the criteriacharacteristics pertain to physical appearance of the items.
 4. Themethod according to claim 3, wherein the criteria characteristics thatpertain to physical appearance of the items are selected from the groupconsisting of type, shape and color.
 5. The method according to claim 2,the specific criteria are ascertained by detecting characteristics ofthe individual items prior to entry thereof into said sorting-out pathand feeding characteristics detected to said control unit.
 6. A methodaccording to claim 1, further comprising the steps of presorting theitems according to subcriteria and placing the items in respectivededicated positions on an infeed conveyor of the weighing station, thecontrol unit keeping track of the absolute positions of said dedicatedpositions.
 7. A method according to claim 1, comprising the further stepof ascertaining a relevant criterion characteristic pertaining to anaction to which a selectable item should be subjected upon its deliveryto a receiver station and prior to its being finally rested in arespective final group based on special conditions for the building-upof just that group, and performing the required action with respect toall items allocated to a selected receiver substation in response todetection of a color marking or changed orientation of the item.
 8. Themethod according to claim 1, wherein at least two combined receiverstations are provided such that at least one of the combined receiverstations is operated such that items allocated thereto are collected inseparately packed subgroups which are thereafter transferred to arespective final group.
 9. A weighing-out apparatus of the grader typecomprising: a weighing-in station, a sorting-out path extending from theweighing-in station, a row of receiver stations located along saidsorting-out path, diverter means for selectively diverting selecteditems from said sorting-out path to respective receiver stations, acontrol unit for controlling the diverter means and connected with theweighing station, said control unit being adapted to build up itemgroups of predetermined accumulated weights in the receiver stations,wherein at least some of the receiver stations are operationally andphysically grouped as receiver substations in such a manner that theywill deliver their received items to a single final group collectorhaving a final batch weight, and wherein the control unit is programmedso as to decide, for each item, whether the item should be allocated toone or another receiver substation wherein allocation of the item to aparticular substation is controlled such that the weight of at least oneof the substations compensates for the weight of other substations inorder to provide a final batch weight within a predetermined tolerance.10. An apparatus according to claim 9, wherein each of the receiverstations comprises an upper receiving mouth opening and chute means forguiding received items to underlying collector means located below saidmouth opening, said chute means being arranged so as to be common fortwo or more of said grouped receiver substations.
 11. An apparatusaccording to claim 9, comprising detector means for detecting a relevantcriterion characteristic of the incoming items.
 12. A method ofcontrolling operation of a weighing-out apparatus of the grader typehaving a weighing-in station, a sorting-out path, at least one row ofreceiver stations with associated diverter means for enabling selectivetransfer of items to said receiver stations, a conveyor for movingarticles serially through said weighing-in station and along asorting-out path, at least one row of receiver stations arranged alongsaid sorting-out path, a control unit connected with the weighing-instation, comprising the steps of: serially conveying articles throughsaid weighing-in station, weighing the articles and conveying thearticles weighed along said sorting-out path, using said control unit tooperate said diverter means in a manner effecting an accumulative andweight determined build-up of desired groups of items in respectivereceiver stations, using at least two of the receiver stations as asingle combined station, items being allocated to the receiver stationsof the combined station by the control unit as a single batch with anassociated target weight using specific criteria for determining whetheritems should be allocated to a respective one of the receiver stationsof the combined station, or to any one of a number of other suchcombined receiver stations; and merging of items allocated to thereceiver stations of the combined station.
 13. The method according toclaim 12, wherein said specific criteria pertain to physicalcharacteristics other than item weight.
 14. The method according toclaim 13, wherein the criteria characteristics pertain to physicalappearance of the items.
 15. The method according to claim 14, whereinthe criteria characteristics that pertain to physical appearance of theitems are selected from the group consisting of type, shape and color.16. The method according to claim 12, the specific criteria areascertained by detecting characteristics of the individual items priorto entry thereof into said sorting-out path and feeding characteristicsdetected to said control unit.